Condition

Onchocerciasis (river blindness)

Medical reviewer Mr Mohamed Mohyudin, Consultant Ophthalmic SurgeonArticle reviewed

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Onchocerciasis (river blindness) at a glance

Side-view diagram of the eye with the cornea, retina and optic nerve highlighted: the parts of the eye involved in onchocerciasis.
Where it affects the eye: Cornea, retina and optic nerve. Simplified side view of the eye. It shows location, not how severe a condition is.
Part of the eye
Cornea, retina and optic nerve
Common signs
  • Intense itching and skin nodules
  • Thickened or leopard-spot skin
  • Eye redness, pain and light sensitivity
  • Progressive vision loss and blindness in untreated cases
Treatment options
Condition group
Retina and optic nerve
Medical code (ICD-10)
B73

What is onchocerciasis (river blindness)?

Onchocerciasis is caused by the worm Onchocerca volvulus, transmitted by repeated black fly bites. Microfilariae migrate through skin and eyes, causing inflammation that can damage the cornea and optic nerve over years.

Symptoms of onchocerciasis

Symptoms build over years of exposure in endemic communities.

  • Intense itching and skin nodules
  • Thickened or leopard-spot skin
  • Eye redness, pain and light sensitivity
  • Progressive vision loss and blindness in untreated cases

WHO prevention and control

WHO and partners run community treatment with ivermectin (Mectizan) to kill microfilariae and prevent transmission. Vector control near rivers also helps. The goal is elimination as a public health problem in affected countries.

Relevance elsewhere

River blindness is rare in high-income countries. Travellers to endemic areas for long periods may need awareness, but tourist visits are very low risk. It illustrates why global eye health programmes matter alongside everyday conditions elsewhere.

Treatments & Surgery

Mass drug administrationHow WHO community treatment programmes distribute medicines to prevent trachoma and river blindness — public health, not self-treatment.

Frequently asked questions

Is onchocerciasis still a cause of blindness?

Yes in some endemic regions, though WHO-led mass drug administration has dramatically reduced new blindness in many African countries.

How is river blindness prevented?

Community treatment with ivermectin and fly control near rivers are the main WHO-backed strategies, repeated until transmission stops.

Can onchocerciasis be treated?

Ivermectin kills microfilariae and reduces progression, but established eye scarring may be permanent, which is why prevention programmes focus on early community treatment.

Your next step

Take this to your appointment

Write down what has changed, when it started, your current medicines and the questions you want answered. Take these to your eye-care appointment.

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Sudden loss of sight, severe eye pain or a dark curtain across vision needs immediate assessment. Do not wait to complete a worksheet.

Sources for this information

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